【spring】spring有哪几种配置方式

一、说明

• 1.spring有三种重要的方法提供配置元数据

二、配置方式

• 1.基于xml配置文件，spring诞生的一种配置方式
• 2.基于注解的配置，spring2.5+开始
• 3. 基于java的配置，javaConfig，spring3.0+开始

三、配置示例

3.1 基于xml配置文件

• 1.文件名为spring.xml，文件位置放入resources中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context.xsd">
	<bean id="userService" class="com.learning.beanconfig.UserService"></bean>
</beans>

package com.learning.beanconfig;

/**
 * @Author wangyouhui
 * @Description 服务类
 **/
public class UserService {
	public void print(String hello) {
		System.out.println(hello);
	}
}

package com.learning.beanconfig;

import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @Author wangyouhui
 * @Description 应用类
 **/
public class Application {
	public static void main(String[] args) {
		ClassPathXmlApplicationContext classPathXmlApplicationContext = new ClassPathXmlApplicationContext("spring.xml");
		UserService userService = (UserService)classPathXmlApplicationContext.getBean("userService");
		userService.print("hello");
	}
}

3.2 基于注解的配置

• 1.文件名为spring-annotation.xml，文件位置放入resources中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
	http://www.springframework.org/schema/beans/spring-beans.xsd
	http://www.springframework.org/schema/context
	http://www.springframework.org/schema/context/spring-context.xsd">
	<!-- 设置自动扫描的包 -->
	<!-- base-package：设置一个基础包，Spring会自动扫描该包及其子包下的组件 -->
	<context:component-scan base-package="com.learning.beanannotation">

	</context:component-scan>
</beans>

package com.learning.beanannotation;

import org.springframework.stereotype.Component;

/**
 * @Author wangyouhui
 * @Description 服务类
 **/
@Component
public class UserService {
	public void print(String hello) {
		System.out.println(hello);
	}
}

package com.learning.beanannotation;

import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @Author wangyouhui
 * @Description 应用类
 **/
public class Application {
	public static void main(String[] args) {
		ClassPathXmlApplicationContext classPathXmlApplicationContext = new ClassPathXmlApplicationContext("spring-annotation.xml");
		UserService userService = (UserService)classPathXmlApplicationContext.getBean("userService");
		userService.print("hello");
	}
}

3.3 基于java的配置

• 1.这里是@Configuration注解，@Bean @Import等暂不介绍

package com.learning.beanjavaconfig;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@Configuration//作为配置类，代替xml文件
@ComponentScan(basePackages = {"com.learning.beanjavaconfig"})
public class SpringConfig {
}

package com.learning.beanjavaconfig;

import org.springframework.stereotype.Component;

/**
 * @Author wangyouhui
 * @Description 服务类
 **/
@Component
public class UserService {
	public void print(String hello) {
		System.out.println(hello);
	}
}

package com.learning.beanjavaconfig;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

/**
 * @Author wangyouhui
 * @Description 应用类
 **/
public class Application {
	public static void main(String[] args) {
		AnnotationConfigApplicationContext annotationConfigApplicationContext = new AnnotationConfigApplicationContext(SpringConfig.class);
		UserService userService = (UserService)annotationConfigApplicationContext.getBean("userService");
		userService.print("hello");
	}
}